Process for surface functionalsation of polymeric substrates using diaryl carbenes as reactive intermediates

ABSTRACT

A process for the surface functionalisation of a polymeric substrate, which process comprises:
         (a) contacting the substrate with a diarylcarbene precursor,   (b) generating a carbene reactive intermediate from the diarylcarbene precursor so that it reacts with the substrate to functionalise the surface, and   (c) further functionalising the activated substrate obtained in step (b).

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of Ser. No. 09/830,829 filed Aug. 21,2001 now U.S. Pat. No. 6,699,527, which claimed priority fromPCT/GB99/03629 filed Nov. 3, 1999.

The present invention relates to a process for the surfacefunctionalisation of a polymeric substrate using diarylcarbenes as thereactive intermediates. The invention in particular relates to a processfor the surface functionalisation, for example dyeing, of substratessuch as cotton, a variety of plastics, polystyrene, nylon, controlledpore glass, silica, an ethylene polymer or polytetrafluoroethylene.

Dyestuffs which are used to colour natural and synthetic polymers, viacovalent modification, most commonly rely upon the presence of highlyreactive groups which have been coupled to the chromophoric species.Examples include the Procion and Gibacron range of dyes (which rely uponthe reactivity of a chlorotriazinyl residue with nucleophilic residueson the substrate), the Remazol range of dyes (which rely on avinylsulfonyl residue as a nucleophilic acceptor) and the Drimalon rangeof dyes (which contain an α-chloroacetyl residue as the reactivespecies). Modifications of these reactive entities have been developed,leading to other related dye classes (e.g. the Drimarenes and Reactones,which use a tetrachloropyrimidine reactive unit, and the Primazin dyes,which use an acrylamide residue). Each of these reactive classes of dyehave preferred substrates, although all contain aromatic or vinylicgroups which are particularly activated towards nucleophilic attack bysuitable functionality on the substrate. Development of this type ofstrategy still continues. However, in addition to the requirement fornucleophilic functionality on the substrate (which would usually behydroxyl or amino groups), this approach generally requires vigorousconditions, such as high temperature or strongly basic media, for bondformation to occur.

An alternative technique whereby highly reactive carbene or nitrenespecies are generated from inert precursors under less harsh photolytic,and sometimes thermolytic, conditions has also been investigated forapplication to dyeing and other surface modifying processes of variousnatural and synthetic polymers. The chemistry of cargenes and nitrenesis well documented, and these reactive entities are known to formcovalent bonds with many types of functional groups. The application ofthese species to the surface modification or organic solids usingdifferent approaches both for the generation of the required carbenes ornitrenes, and for their reaction with the solid surface has beenreported. Interestingly, although nitrenes (often generated from anazide or sulfonylazide precursor under photolytic or thermolyticconditions) are more stable, and therefore less reactive, than theircarbene analogues, they have used much more widely for the dyeing ofpolymeric substrates.

French Patent No. 1 500 512 discloses allowing carbenes to come intocontact with an organic solid. The preferred method for surfacemodification is to allow the volatilised carbene to come into contactwith the polymer. Inherent in this approach, however, are limitations:only volatile (i.e. low molecular weight) carbenes, and those stable torelatively high temperatures, are applicable.

The application of carbenes generated from diazo compounds as suitablereactive dyes has been found to have important limitations, for examplethe ease of generation of the required diazo precursor (D. R. Braybrooket al., J. Photochem. Photobiol A: Chem, 1993, 70, 171) and thestability of the dye to the carbene generating process.

The present invention provides a process which may allow the surfacefunctionalisation of materials which have hitherto been difficult tomodify, for example glass or a variety of plastics. The process of thepresent invention may also allows greater flexibility than knownprocesses in which a single carbene insertion step introduces thedesired functionality. In addition, it is supposed that substrates whichare dyed according to the process of the invention may exhibit superiorwash-fastness to substrates dyed using existing processes due to areduction in hydrolysable bonds on the surface of the substrate.

In a first aspect the present invention provides a process for thesurface functionalisation of a polymeric substrate, which processcomprises:

-   -   (a) contacting the substrate with a diarylcarbene precursor,    -   (b) generating a carbene reactive intermediate from the        diarylcarbene precursor so that it reacts with the substrate to        functionalise the surface, and    -   (c) further functionalising the activated substrate obtained in        step (b).

In another aspect of the present invention steps (b) and (c) arecombined.

The substrate may be any natural or synthetic polymeric substrate whichis capable of reaction with a carbene reactive intermediate generatedfrom a diarylcarbene precursor. The molecular weight of the polymericsubstrate may be selected according to the desired processability of thefinal product. Typically the substrate is cotton, plastic, polystyrene,nylon, controlled pore glass, silica, an ethylene polymer orpolytetrafluoroethylene.

By “diarylcarbene precursor”, as used herein, is meant a diaryl speciescapable of venerating a carbene reactive intermediate under the reactionconditions. The diarylcarbene precursor must be such that the carbenereactive intermediate generated can react with the polymeric substrateand the activated substrate can be further functionalised.

Preferably the diarylcarbene precursor is a compound of formula I

wherein

-   R is Ar¹ or (CH₂)_(m)N(R¹)(R²);    -   Ar¹ is

-   -   -   wherein Y is C₁ to C₄ alkoxy or N(R³)(R⁴),            -   R³ and R⁴, which may be the same or different, are C₁ to                C₄ alkyl,        -   n is an integer of 0 to 3;

    -   R¹ is C₁ to C₄ alkyl;

    -   R² is phenyl;

    -   m is an integer of 1 to 4; and

-   X is N₂.

More preferably the diarylcarbene precursor is4-([3,4-dimethoxyphenyl]oxymethyl)phenyl phenyl diazomethane1,4-([3-N,N-diethylaminophenyl]-oxymethyl)phenyl phenyl diazomethane 2or 4-([N-ethyl-N-phenyl-2-aminoethyl]oxymethyl)phenyl phenyldiazomethane 3.

Typically the diaryl diazomethane compounds are stable and may be storedat 0° C. for extended periods.

Diarylcarbene precursors 1 and 2 may be prepared as shown in Scheme 1.4-Bromomethylbenzophenone, which can be prepared according to D. D.Tanner et al. J. Org. Chem., 1980, 45, 5177, is first coupled with thedesired aryl alcohol. The resulting benzophenone may be converted to thehydrazone by treatment in refluxing ethanol overnight, followed byremoval of the solvent and extraction into dichloromethane. Oxidation ofthe hydrazone to the corresponding diazo diarylcarbene precursor mayconveniently be performed with mercuric oxide in ether.

Diarylcarbene precursor 3 may be prepared similarly as shown in Scheme2.

By “carbene reactive intermediate”, as used herein, is meant a reactivespecies comprising a formally divalent carbon atom. The carbene reactiveintermediate is generated from the diarylcarbene precursor by treatmentunder conditions which result in an irreversible covalent reaction withthe substrate. Generally the carbene is generated by heating thesubstrate and pre-adsorbed diazo compound, or by irradiation. Typically,the substrate is heated for the time required for decolourisation. Inone embodiment of the present invention part of the surface of thesubstrate is activated by selective heating or irradiation, for exampleby photoactivation using a laser. This may allow the controlled andselective modification of a two-dimensional polymer surface and may beuseful in two-dimensional data storage such as CD data storage.

The activated substrate obtained in step (b) is further functionalised.By “functionalise”, as used herein, is meant the introduction of a oranother chemical functional group, which exhibits desirable physical orchemical properties, by irreversible covalent attachment. The activatedsubstrate may be further functionalised by, for example, a dye,fluorescent brightener, UV-absorber, anti-static agent, flame retardant,surface finish, non-linear optical function, chelating function,electrically conducting function, magnetic function or polarisingfunction.

The dye may be any suitable diazonium compound, for example acommercially available diazonium compound which may be selected toobtain the desired colour such as red, yellow, orange or blue. Thecolour may be altered in some cases by adjustment of pH of the finalpolymer sample by suitable treatment with acid or base. Examples ofsuitable diazonium compounds include those of formulae II, III or IV

wherein

-   R⁵ and R⁶, which may be the same or different, are NO₂ or SO₃Na;-   R⁷ and R⁸, which may be the same or different, are C₁ to C₄ alkoxy,    preferably methoxy;-   Ar² is

-   -   wherein R⁹ is C₁ to C₄ alkyl and q is an integer of 0 to 3,        preferably 0;        and

-   X is fluorine, chlorine, bromine or iodine.

The activated substrate may also be functionalised by, for example,introduction of a phthalocyanine functional group.

The process of the invention may find application in, for example, thedye industry, or combinatorial or polymer chemistry. More particularlythe process of the present invention may find application in thepreparation of immobilised catalysts, immobilised colours and dyes,photoelectric/solar cells, conducting (including photoelectric andsemiconducting) polymers, magnetic polymers and optical recording andnon-linear optical devices.

The process of the present invention may also be used in the preparationof biocidal or biostatic fabrics and plastics which have applicationsin, for example, water purification, medical and military clothing(where biocidal activity would help to minimise the transfer ofinfective agents or infections due to injury in the field) and surfaceanti-fouling of, for example, ship hulls, showers or tubing. Theactivated substrate obtained in step (b) of the process of the presentinvention may be functionalised by, for example, a chemical functionalgroup comprising an antibiotic; a heavy metal such as silver, copper orzinc; a quaternary ammonium salt; a phosphonium salt; an oxidising agentsuch as an N-halamine or precursor thereof for example chloramine,chlorine, hydrogen peroxide or iodine; or a phenolic group. According tothe process of the present invention the polymeric substrate may be, forexample, a polymeric thread or a finished textile. The surfacefunctionalised substrates prepared by the process of the presentinvention may be durable to repeated use and laundry, and may beregenerable. For example, the activated substrate obtained in step (b)may be functionalised using a urea hydroperoxide functional group whichwould be regenerable by treatment with hydrogen peroxide or anN-halamine functional group which would be regenerable with a chlorinesolution such as hypochlorite bleach.

In a further aspect the present invention provides diarylcarbeneprecursors of formula I as defined above.

The Examples which follow further illustrate the present invention.

EXAMPLES

UV spectra were recorded on a Perkin Elmer 555 UV-visible spectrometer.IR spectra were obtained as Nujol mulls, or as liquid films, and wererecorded on a Perkin Elmer 781 spectrophotometer: broad (br), weak (w),medium (m) and strong (s) bands are reported.

¹H NMR spectra were recorded on a Varian Gemini 200 MHz spectrometerusing the solvents (CDCl₃ or (CD₃)₂CO) as internal standards.Multiplicities are recorded as s (singlet), d (doublet), t (triplet), q(quartet) and m (multiplet).

Mass spectra were recorded on VG Analytical Ltd. ZAB1F or MM30F massspectrometers (probe ammonia chemical ionisation (CI NH₃), positiveargon fast atom bombardment (FAB) and electron impact (EI)).

Melting points were recorded on a Stuart Scientific SMP1 melting pointmachine and are uncorrected.

Flash chromatography was performed using Merck silica gel. Eluants usedwere as indicated in the text and the following solvents were dried andpurified before use according to standard procedures: dichloromethanewas refluxed and distilled over calcium hydride, ethyl acetate wasdistilled and the first 20% of the distillate was discarded, petroleumether (b.p. 60–80° C.) was distilled and the first 20% of the distillatewas discarded. THF was refluxed and distilled over sodium benzophenoneketyl under an atmosphere of argon. When necessary, solvents weredegassed using a water pump for 15 min. Thin layer chromatography wasperformed on Merck 60 F₂₅₄ Art.5554 precoated silica plates and productspots were visualised under UV conditions at 254 nm.

Benzophenone hydrazone was purchased from Aldrich.

Preparation of Diarylcarbene Precursors

General Method A for the Formation of Benzophenone Hydrazones.

The required benzophenone was refluxed in ethanol and hydrazine hydrateovernight. The solvent was removed in vacuo and the residue dissolved inDCM, washed with water, dried and concentrated under vacuum. Thehydrazones, which were obtained as inseparable mixtures of the syn- andanti-isomers, were then used without further purification.

General Method B for the Formation of Diphenyl Diazomethanes

The required benzophenone hydrazone was dissolved in Et₂O and stirredvigorously with yellow mercuric oxide (1.2 eq), sodium sulphate andsaturated KOH in ethanol. Stirring was continued overnight and themixture was filtered through Celite®. Excess solvent was removed undervacuum and the product was used without further purification.

4-Bromomethylbenzophenone

A stirred mixture of 4-methylbenzophenone (15.02 g, 76.6 mmol) andN-bromosuccinimide (14.2 g, 79.8 mmol) in CHCl₃ (100 cm³) was heatedunder gentle reflux for 18 h with a 100 W bulb shining 2 cm from theflask. The reaction mixture was washed with water, dried (MgSO₄) andsolvent was removed in vacuo). The resulting solid was then washed withEt₂O to remove any starting material to leave the product as a whitesolid (15.07 g, 71.5%, mp 110–112° C. (lit. 110–111°); δ_(H) (200 MHz;CDCl₃) 4.55 (2 H, s, CH ₂Br), 7.46–7.70 (5 H, m, ArH), 7.80–7.9 (4 H, m,ArH o- to C═O); m/z 277 ([M⁸¹Br+H]⁺, 25%) and 275 ([M⁷⁹Br+H]⁻, 25%), 197(100%).

4-([3,4-Dimethoxyphenyl]oxymethyl)benzophenone 1′

To 3,4-dimethoxyphenol (1.69 g, 11 mmol) in THF was added NaH (60%dispersion in oil, 1.2 eq., 0.53 g) and stirring continued for 1 hour.4-Bromomethyl benzophenone (3.01 g, 11 mmol) was then added to thesolution and stirring continued for a further 24 hours. The solution wasconcentrated in vacuo, diluted with DCM, washed with citric acid (10%aq.), NaOH (1N) dried and solvent removed under vacuum. The residue wasthen purified by column chromatography, eluting with petrol(40–60):EtOAc 9:1 yielding the product as a white solid (2.58 g, 68%)(Found: C, 75.73; H, 5.96. C₂₂H₂₀O₄ requires C, 75.84; H, 5.79%), mp74–75° C.; R_(f)=0.23 (Petrol:EtOAc 4:1); δ_(H) (250 MHz, CDCl₃) 3.82 (3H, s, OCH ₃), 3.86 (3 H, s, OCH ₃), 5.10 (2 H, s, CH ₂), 6.47 (1 H, dd,J 9, 1, ArH p- to OMe), 6.65 (1 H, d, J 1, ArH o- to 2 OR), 6.80 (1 H,d, J 9, ArH m- to 2 OR), 7.47–7.75 (5 H, m, ArH), 7.80–7.91 (4 H, m, ArHo- to C═O); δ_(C) (50.3 MHz, CDCl₃) 55.8 (OCH₃), 56.4 (OCH₃), 69.9(CH₂O), 101.2 and 104.0 (ArCH o- to OCH₂Ar), 111.7 (ArCH m- to OCH₂Ar),127.0, 128.3, 130.0 and 130.3 (ArCH o- and m- to C═O), 132.5 (ArCH p- toC═O), 137.0 and 137.5 (4° ArCC═O), 141.9 (ArCCH₂O), 143.8 (4° ArCOCH₂),149.9 (4° ArCOMe p- to OCH₂Ar), 153.0 (4° ArCOMe m- to OCH₂Ar), 196.3(C═O); m/z (APCl⁺) 349 ([M+H]⁺, 100%).

4-([3,4-Dimethoxyphenyl]oxymethyl)benzophenone Hydrazone

The benzophenone 1′ (1.52 g, 4.36 mmol) was reacted with hydrazinehydrate according to General Method A yielding the hydrazone as a yellowoil (1.50 g, 95%), δ_(H) (200 MHz, CDCl₃) 3.76, 3.77, 3.79 and 3.81 (6H, 4* s, OCH ₃), 4.91 and 5.03 (2 H, 2* s, CH ₂), 5.47 (2 H, br s, NH₂), 6.40 and 6.46 ((1 H, 2*dd, J9, 1, ArH p- to OMe), 6.55 and 6.60 (1H, 2* d, J 1, ArH o- to 2 OR), 6.68 and 6.73 (1 H, 2* d, J 9, ArH m- to2 OR), 7.20–7.60 (9 H, m, ArH); δ_(C) (50.3 MHz, CDCl₃) 55.7 (OCH₃),56.3 (OCH₃), 70.0 (CH₂O), 101.2 and 104.0 (ArCH o- to OCH₂Ar), 111.8(ArCH m- to OCH₂Ar), 126.4, 126.5, 127.3, 128.0, 128.1, 128.5, 128.8,128.9, 129.1 and 129.4 (ArCH o- and m- to C═N), 132.5 and 132.9 (ArCH p-to C═N), 136.9, 137.9, 138.2 and 138.4 (4* ArCC═N), 143.6 and 143.8 (4°ArCCH₂O), 148.1 (4° ArCOCH₂), 149.8 and 149.9 (4° ArCOMe p- to OCH₂Ar),153.2 (ArCOMe m- to OCH₂Ar); m/z (APCl⁺) 363 ([M+H]⁺, 100%).

4-([3,4-Dimethoxyphenyl]oxymethyl)phenyl Phenyl Diazomethane 1

The above benzophenone hydrazone (1.50 g, 4.14 mmol) was reacted withmercuric oxide and sodium sulphate according to General Method Byielding the diazomethane as a purple oil (1.35 g, 91%) (Found: C,73.85; H, 5.33; N, 7.31. C₂₂H₂₀N₂O₃ requires C, 73.32; H, 5.59; N,7.77%), v_(max)(film)cm/⁻¹ 2038 (s), 1595 (m), 1511 (s); δ_(H) (500 MHz,CDCl₃) 3.85 (3 H, s, OCH ₃), 3.87 (3 H, s, OCH ₃), 5.02 (2 H, s, CH ₂),6.49 (1 H, dd, J 9, 1, ArH p- to OMe), 6.62 (1 H, d, J 1ARH o- to 2 OR),6.80 (1 H, d, J 9, ArH m- to 2 OR), 7.16–7.49 (9 H, m, ArH); δ_(C)(125.8 MHz, CDCl₃) 55.8 (OCH₃), 56.4 (OCH₃), 70.2 (CH₂O), 101.2 and104.0 (ArCH o- to OCH₂Ar), 111.6 (ArCH m- to OCH₂Ar), 125.1, 125.2,128.5 and 129.1 (ArCH o- and m- to C═N), 125.7 (ArCH p- to C═N), 129.3and 129.4 (4° ArCC═N), 134.4 (4° ArCCH₂O), 143.6 (4° ArCOCH₂), 149.8 (4°ArCOMe p- to OCH₂Ar), 153.3 (4° ArCOMe m- to OCH₂Ar).

4-([3-N,N-Diethylaminophenyl]oxymethyl)benzophenone 2′

3-N,N-Diethylaminophenol (3.03 g, 18.4 mmol, 1.2 eq) in THF (20 cm³) wastreated with NaH (60% dispersion in oil, 524 mg, 13.1 mmol, 1.4 eq) andstirred at 20° C. for 1 hour. 4-Bromomethylbenzophenone (4.21 g, 15.3mmol) was then added and stirring continued for 72 hours. Excess solventwas removed in vacuo and the residue diluted with DCM, washed with waterand NaHCO₃ solution (sat.), dried (MgSO₄) and solvent removed undervacuum. The resulting oil was purified by flash chromatography, elutingwith petroleum (bp 40–60° C.):EtOAc (9:1), to give the desired productas a yellow oil (4.29 g, 65%), R_(f)=0.51 (4:1, petrol:EtOAc) (Found: C,79.99; H, 7.13; N, 5.23. C₂₄H₂₅NO₂ requires C, 80.19; H, 7.01; N, 3.90%;v_(max) (film)/cm⁻¹ 1657 (s), 1610 (s); δ_(H) (500 MHz; CDCl₃) 1.17 (6H, t, J 7, CH ₃), 3.35 (4H, q, J 7, CH ₂CH₃), 5.16 (2 H, s, ArCH ₂O),6.27–6.40 (3 H, m, ArH o- and p- to NEt₂), 7.15 (1 H, dd, J 7, 7, ArH m-to NEt₂), 7.45–7.66 (5 H, m, ArH), 7.80–7.89 (4 H, m, ArH o- to C═O);δ_(C) (125.8 MHz; CDCl₃) 12.6 (CH₃), 44.4 (NCH₂CH₃), 69.2 (ArCH₂O),99.1, 100.8 and 105.4 (ArCH o- and p- to NEt₂), 127.0, 128.3, 130.0 and130.4 (ArCH), 132.4 (ArCH p- to C═O), 136.9 and 137.6 (4° ArCC═O), 142.3(4° ArCCH₂O), 149.2 ArCNEt₂), 159.9 (4° ArCOCH₂), 196.4 (C═O); m/z(APCl⁺) 360 ([M+H]⁻, 100%).

4-([3-N,N-Diethylaminophenyl]oxymethyl)benzophenone Hydrazone

The benzophenone 2′ (1.76 g, 1.95 mmol) was reacted with hydrazinehydrate according to General Method A yielding the hydrazone as acolourless oil (1.31 g, 72%), (Found: C, 76.26; H, 7.30; N, 12.47.C₂₄H₂₇N₃O requires C, 77.18; H, 7.29; N, 11.25%); v_(max)(film)/cm⁻¹1605 (m); δ_(H) (200 MHz CDCl₃) 1.24–1.34 (6 H, m, CH ₃), 3.39–3.54 (4H, m, NCH ₂CH₃), 5.16 and 5.24 (2 H, 2* s, ArCH ²O), 5.61 (2 H, br s,NNH ₂), 6.45–6.52 (3 H, m, ArH o- and p- to NEt₂), 7.25–7.77 (10 H, m,ArH); δ_(C) (50.3 MHz; CDCl₃) 12.7 (CH₃), 44.5 (NCH₂CH₃), 69.6 and 69.7(ArCH₂O), 99.4 and 99.5, 101.1 and 101.2, 105.6 and 105.7 (ArCH o- andp- to NEt₂), 126.8, 127.0, 127.7, 128.1, 128.4, 128.5, 128.9, 129.2,129.5, 129.8, 130.3, 130.4, 132.8, 133.3, 137.7, 138.5, 138.7, 138.7 and138.9 (ArCH, 4° ArCC═N and 4° ArCCH₂O), 148.8 (C═NNH₂), 149.5 (4°ArCNEt₂), 160.6 (4° ArCOCH₂); m/z (APCl⁺) 374 ([M+H]⁺, 15%), 209 (100),195 (50), 178 (75).

4-([3-N,N-Diethylaminophenyl]oxymethyl)phenyl Phenyl Diazomethane 2

The above benzophenone hydrazone (1.30 g, 3.49 mmol) was stirredvigorously with yellow mercuric oxide (1.40 g, 6.5 mmol), anhydroussodium sulphate (2.00 g, 14.1 mmol) in diethyl ether (33 cm³) andsaturated KOH in ethanol (1 cm³) for 18 hours. The solution was filteredthrough Celite® and solvent removed in vacuo yielding the product as ared oil (1.22 g, 94%), v_(max)(film)/cm⁻¹ 2037 (s), 1612 (m); δ_(H) (200MHz; CDCl₃) 1.27 (6 H, m, CH ₃), 3.44 (4 H, m, NCH ₂CH₃), 5.15 (2 H, s,ArCH ₂O), 6.42–6.50 (3 H, m, ArH o- and p- to NEt₂), 7.21–7.55 (10 H, mArH); δ_(C) (50.3 MHz; CDCl₃) 12.8 (CH₃), 44.5 (NCH₂CH₃), 69.6 (ArCH₂O),99.3, 101.0 and 105.5 (ArCH o- and p- to NEt₂), 128.2, 128.6, 128.7,129.2 and 129.3 (ArCH o- and m- to C═N and ArCH m- to NEt₂), 130.0 (ArCHp- to C═N), 132.5 and 133.0 (4° ArCC═N), 135.0 (4° ArCCH₂O), 149.2 (4°ArCNEt₂), 160.3 (4° ArCOCH₂).

4-([N-Ethyl-N-phenyl-2-aminoethyl]oxymethyl)benzophenone

2-(N-Ethylanilino)ethanol (3.03 g, 18.4 mmol, 1.2 eq) in THF (20 cm³)was treated with NaH (60% dispersion in oil, 524 mg, 13.1 mmol, 1.4 eq)and stirred at 20° C. for 1 hour. 4-Bromomethylbenzophenone (4.21 g,15.3 mmol) was then added and stirring continued for 72 hours. Excesssolvent was removed in vacuo and the residue diluted with DCM, washedwith water and NaHCO₃ solution (sat.), dried (MgSO₄) and solvent removedunder vacuum. The resulting oil was purified by flash chromatography,eluting with petroleum (bp 40–60° C.):EtOAc (9:1), to give the desiredproduct as a yellow oil (4.36 g, 80%), R_(f)=0.54 (4:1, petrol:EtOAc)(Found: C, 78.34; H, 6.86; N, 5.29. C₂₄H₂₅NO₂ requires C, 80.19; H,7.01; N, 3.90%); v_(max) (film/cm⁻¹ 1658 (s), 1598 (s), 1506 (s); δ_(H)(200 MHz; CDCl₃) 1.22 (3 H, t, J 7, CH ₃), 3.49 (2 H, q, J 7, CH ₂CH₃),3.58–3.79 (4 H, m, OCH ₂CH ₂N), 4.66 (2 H, s, ArCH ₂O), 6.69–6.79 (3 H,m, ArH o- and p- to NR₂), 7.28 (2 H, dd, J 7, 7, ARH m- to NR₂),7.46–7.68 (5 H, m, ArH), 7.80–7.88 (4 H, m, ArH o- to C═O); δ_(C) (50.3MHz; CDCl₃) 12.2 (CH₃),45.5 (NCH₂CH₃), 50.1 (NCH₂CH₂O), 68.5 (NCH₂CH₂O), 72.2 (ArCH₂O), 111.8 (ArCH o- to NR₂), 115.8 (ArCH p- to NR₂),127.0, 128.3, 129.3, 130.0 and 130.3 (ArCH o- and m- to C═O and ArCH m-to NR₂), 132.4 (ArCH p- to C═O), 136.8 and 137.7 (4° ArCC═O), 143.2 (4°ArCCH₂O), 147.7 (4° ArCNR₂), 196.4 (C═O); m/z (APCl⁺) 360 ([M+H]⁺, 30%);HRMS C₂₄H₂₆O₂N requires 360.1963; found 360.1963.

4-([N-Ethyl-N-phenyl-2-aminoethyl]oxymethyl)benzophenone Hydrazone

The above benzophenone (701 mg, 1.95 mmol) was reacted with hydrazinehydrate according to General Method A yielding the hydrazone as acolourless oil (710 mg, 97%), v_(max) (film)/cm⁻¹ 1598 (s), 1506 (s);δ_(H) (500 MHz; CDCl₃) 1.27 and 1.31 (3 H, 2* t, J 7, CH ₃), 3.52 and3.57 (2 H, 2* q, J 7, CH ₂CH₃), 3.60–3.87 (4 H, m, NCH ₂CH ₂O), 4.63 and4.71 (2 H, 2* s, ArCH ₂O), 5.57 (2 H, br s, NNH ₂), 6.76–6.87 (3 H, m,ArH o- and p- to NR₂), 7.30–7.42 (7 H, m, ArH), 7.53–7.64 (4 H, m, ArHo- to C═N); δ_(C) (125.8 MHz; CDCl₃) 12.0 (CH₃), 45.1 and 45.2(NCH₂CH₃), 49.8 (NCH₂CH₂O), 67.8 and 68.1 (OCH₂CH₂N), 72.6 and 72.7(ArCH₂O), 111.5 and 111.6 (ArCH o- to NR₂), 115.5 and 115.6 (ArCH p- toNR₂), 126.2, 127.1, 127.7, 127.8, 128.1, 128.5, 128.6, 128.9, 129.0 and129.1 (ArCH), 131.9 and 132.8 (4° ArCCH₂O), 137.7, 137.8, 138.3 and138.9 (4° ArCC═N), 147.5 (4° ArCNR₂), 148.1 (C═NNH₂); m/z (APCl⁺) 374([M+H]⁺, 5%), 357 (5%), 209 (100%).

4-([N-Ethyl-N-phenyl-2-aminoethyl]oxymethyl)phenyl Phenyl Diazomethane 3

The above benzophenone hydrazone (701 mg, 1.88 mmol) was reacted withmercuric oxide and sodium sulphate according to General Method Byielding the diazomethane as a purple liquid (690 mg, 99%) (Found: C,78.06; H, 6.89; N, 12.36. C₂₄H₂₅N₃O requires C, 77.60; H, 6.78; N,11.31%); v_(max) (film)/cm⁻¹ 2037 (s), 1559 (m); δ_(H) (500 MHz; CDCl₃)1.26–1.32 (3 H, m, CH ₃), 3.50–3.80 (6 H, m, NCH ₂CH₃ and NCH ₂CH ₂O),4.65 (2 H, s, ArCH ₂O), 6.78–6.86 (3 H, m ArH o- and p- to NR₂),7.28–7.65 (11 H, m ArH); δ_(C) (125.8 MHz; CDCl₃) 12.1 (CH₃), 45.3(NCH₂CH₃), 50.0 (NCH₂CH₂O), 67.9 (OCH₂CH₂N), 72.8 (ArCH₂O), 111.7 (ArCHo- to NR₂), 115.6 (ArCH p- to NR₂), 125.0, 125.5, 126.3, 128.3, 128.4,128.7, 129.0, 129.1 and 129.2 (4° ArC and ArCH), 135.7 (4° ArCCH₂O),147.7 (4° ArCNR₂); m/z (APCl⁻) 344 ([M−N₂]⁺, 20%), 209 (100).

Activation and Functionalisation of Substrates

2-Sulphonyl-4-nitrobenzene Diazonium Chloride (0.1M aq)

To a suspension of 2-amino-5-nitrobenzene sulphonic acid, sodium salt(2.40 g, 10 mmol) in iced water (50 cm³) and HCl (10 N, 5 cm³), NaNO₂ (1M, 11 cm³) was slowly added and stirred vigorously for 5 minutes whilstmaintaining the temperature at 0° C. The solution was made to pH 4 withsodium acetate and diluted to 100 cm³, the diazonium ion was then usedwithout further purification at 0° C. within one hour of formation.

Functionalisation of Substrates

Solutions of the appropriate diazomethane or benzophenone (10–200 mg) indiethyl ether (1–2 ml), or pure ether, were applied to three samples ofthe appropriate polymeric substrate (100 mg–5 g) and the solvent allowedto evaporate at room temperature. One of these samples was taken out andkept aside. The rest of the substrate was then heated, in foil orconical flasks, with a heat gun for the time required to decolourise thesubstrate which had been treated with the diazocompound. Another samplefrom each batch of treated polymer was kept aside at this point. Theremaining substrate was then moistened with ethanol (2 cm³) and asuspension of the diazonium salt (50 cm³, 0.1 M) was added and themixture stirred overnight. The substrate was then removed, washed withwater, hot water and soap, acetone, HCl (1N), NaOH (1N), water andacetone until no further colour leached out of the substrate into theliquid. The substrate was allowed to dry to obtain the final sample.

The use of compounds 1 to 3 for the modification of a range ofsubstrates (cotton, controlled pore glass, polystyrene XAD-40, silicaand nylon membrane) was investigated. Treating each substrate with thediazo compounds and heating to generate the corresponding carbene gavethe surface-modified substrate; this effectively generated an activatedpolymer with the electron-rich aromatic residue attached (Scheme 3).Treatment of the activated polymer with the diazonium salt derived from2-amino-5-nitrobenzene sulphonic acid then gave the correspondingazo-dyed material.

For each substrate, nine controls were run simultaneously (each polymerwas treated with the solvent only, the diazo compounds and theircorresponding benzophenones, either just with the native polymer, withthe native polymer and heating, and with the native polymer, heating andthen adding the diazotisation reagent), in order to verify that anycolouration that arose was due to irreversible bond formation, resultingfrom carbene insertion, and not merely physical adsorption, and theresults are indicated in Table 1. The sample numbering scheme for thecontrols is indicated; samples 1–3 indicate that colouration is notderived simply from modification of the polymer alone in the heating anddiazo treatment process, samples 4–6 indicate that the colourationderives from the diazo coupling reaction (shown in Scheme 3) but thatthis colour washes out, since there was no carbene insertion reactionwhen the benzophenones were used as the substrate. Samples 7–9 indicatethat treatment with both the carbene and diazo coupling agents leads toirreversible colouration.

TABLE 1 DYEING OF VARIOUS SUBSTRATES WITH COMPOUNDS 1, 2 OR 3Functionalising Compound Ether Solvent Diphenyldiazomethane PolymerTreatment only Benzophenone 1, 2 or 3 Native Polymer 1 4 7 After Heating2 5 8 After Diazotization 3 6 9 and washing COTTON: Mercerised WovenCotton Sample Number Compound 1 2 3 4 5 6 7 8 9 1 0 0 0 0 0 + ++ + ++ 20 0 0 0 0 + ++ + +++ 3 0 0 0 0 0 + ++ + +++ POLYSTYRENE: Amberlite XAD-4Non-ionic Polymeric Adsorbant (ex Aldrich Cat No 21, 648-8) SampleNumber Compound 1 2 3 4 5 6 7 8 9 1 0 0 0 0 0 ++ ++ ++ +++ 2 0 0 0 0 0+++ ++ + +++++ ^(†)3  0 0 0 0 0 +++ ++ + +++++ POLYAMIDE: Hybond N (exAmersham Life Science Cat. No. RPN203N) Sample Number Compound 1 2 3 4 56 7 8 9 1 0 0 0 0 0 + ++ + ++ 2 0 0 0 0 0 + ++ + ++++ 3 0 0 0 0 0 + ++ +++++ CONTROLLED PORE GLASS: (ex CPG Inc) Sample Number Compound 1 2 3 45 6 7 8 9 1 0 0 0 n/a n/a n/a n/a n/a n/a 2 0 0 0 n/a n/a n/a n/a n/an/a 3 0 0 0 0 0 + ++ + ++++ FLASH SILICA: (ex Merck) Sample NumberCompound 1 2 3 4 5 6 7 8^(†) 9 1 0 0 0 0 0 + ++ + +++ 2 0 0 0 0 0 + ++ ++++++ 3 0 0 0 0 0 + ++ + ++++ Scale: Colourless Black 0 +++ +++ +++ ++++++++ ^(†)No heat was required for generation of the carbene

1. A diaryl precursor of formula I:

wherein R is Ar¹ or (CH₂)_(m)N(R¹)(R²), Ar¹ is

wherein Y is C₁ to C₄ alkoxy or N(R³)(R⁴), R³ and R⁴, which may be thesame or different, are C₁ to C₄ alkyl, n is an integer of 0 to 3, R¹ isC₁ to C₄ alkyl, R² is phenyl, m is an integer of 1 to 4 and X is N₂. 2.A precursor according to claim 1 wherein R isN-ethyl-N-phenyl-2-aminoethyl, 3,4-dimethoxyphenyl or3-N,N-diethyl-aminopropyl.
 3. 4-([3,4-dimethyoxyphenyl]oxymethyl)phenylphenyl diazomethane.
 4. 4-([3-N,N-diethylaminophenyl]oxymethyl)phenylphenyl diazomethane. 5.4-([N-ethyl-N-phenyl-2-aminoethyl]oxymethyl)phenyl phenyl diazomethane.